Extensible scaffold



Sept. 11, 1956 Filed March 16, 1953 C. A. HARLAN ET AL EXTENSIBLESCAF'FOLD 4 Sneaks-Sheet 2 l6 INVENTORS CAMPBEtL ALLEN HARLAN y JOHNM.HAR.LAN

ATTORNEYS C. A. HARLAN ET AL EXTENSIBLE SCAFFOLD Sept. 11, 1956 4Sheets-Sheet 3 Filed March 16, 1953 3 JOHN M.HARLAN "2% ATTORNEYS FIG.6.

Sept. 11, 1956 c. A. HARLAN ET AL 2,7

EXTENSIBLE SCAFFOLD Filed March 16, 1953 4 Sheets-Shet 4 IN V EN TORSCAMPBELL ALLEN HA R L AN 8 JOHN M.HARLAN Y W ATTORNEYS United StatesPatent EXTENSTBLE SGAFFOLD Campbell Allen Harlan, Birmingham, and JohnM. Harlan, Detroit, Mich.

Application March 16, 1953, Serial No. 342,666

12 Claims. (Cl. 304-29) The present invention relates to an extensiblescaffold, and more particularly, an estensible scaffold including anextensible trackway mounting a vertically movable carrrage.

It is an object of the present invention to provide an estensiblescaffold capable of being lowered to permit its passage through doors orthe like, and capable of being extended to provide a working platform ata substantial elevation.

It is a further object of the present invention to provide an estensiblescafiold characterized by its lightness, its ease and mobility, and itscollapsibility,

It is a further object of the present invention to provide a readilymovable extensible scaffold including power means associated therewithfor raising and lowering the scaffold and for raising and lowering acarriage on the scaffold while the scaffold is either extended orcollapsed.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings, wherein:

Figure 1 is a perspective view of the extensible scaffold.

Figure 2 is a front elevation of the scaffold with parts broken away andparts omitted.

Figure 3 is a fragmentary section on the line 3-3, Figure 2.

Figure 4 is a section on the line 4-4, Figure 2..

Figure 5 is an enlarged fragmentary section on the line 55, Figure 3.

Figure 6 is an end view of the detail shown in Figure 5, looking in thedirection of the arrows 66, Figure 5.

Figure 7 is an enlarged fragmentary section on the line 7-7, Figure 2.

Figure 8 is an enlarged fragmentary section on the line 8-8, Figure 2.

Figure 9 is an enlarged fragmentary section on the line 9-9, Figure 2.

Figure 10 is an enlarged line 1010, Figure 2.

Figure 11 is a fragmentary side elevation showing a modification of thescaffold.

Figure 12 is an enlarged fragmentary side elevation illustrating yetanother modification of the scaffold.

Figure 13 is an enlarged fragmentary section on the line 1313, Figure 4.

Figure 14 is a View similar to Figure 13 showing the relationship ofparts after partial rotation of the drum.

Referring now to the drawings, the extensible scaffold comprises a lowerframe indicated generally at 10 comprising vertically extending rearcorner posts in the form of angle irons 12, and vertically extendingfront corner posts in the form of angle irons 14. The lower ends of theangle irons 12 and 14 are interconnected by side frame members 16 andend frame members 18. The angle irons 12 and 14 are disposed with theirflanges extending parallel to the sides and ends of the frame and withthe concave portion thereof facing inwardly of the frame. At the tops ofthe angle irons 12 and 14 there fragmentary section on the structure.

ice

are provided a pair of side frame members 20 and the rear corner posts12 are interconnected by a cross frame member 22. The upper ends of thefront posts 14 are not directly interconnected, since this space isrequired for movement of a vertically movable frame constructionindicated generally at 24. The lower or main frame 10 however, is bracedby suitable means such for example as the diagonally extending bracerods some of which are designated at 26.

In order to provide easy movement of the scaffold from place to place,the main frame 10 is provided with casters 28.

The vertically movable frame 24 .is telescoped within the main frame 10and comprises rear corner posts 30 and front corner posts 32. The cornerposts 30 and 32 are in the form of angle irons which are nested withinthe angle irons comprising the corner posts 12 and 14 of the main frame.

Inasmuch as the vertically movable frame 24 moves freely within the mainframe 10, its rear corner posts 24 and front corner posts 32 areinterconnected at their bottoms by longitudinally extending angle irons34 and laterally or transversely extending angle irons 36. At the sametime the upper ends of the corner posts of the movable frame 24 areinterconnected by longitudinally extending angle irons 38. The rearcorner posts 30 are interconnected by an angle iron 40. The forwardportions of the longitudinally extending angle irons 38 areinterconnected by a transverse angle iron 42. In addition, a secondangle iron 44 interconnects the front corner posts 32 intermediate theirends by means of brackets 45 as well illustrated in Figure 9. As in thecase of the main frame 10, the movable frame 24 is rendered rigid bydiagonally extending brace members some of which are designated at 46.

A carriage, generally indicated at 50, is provided which is mounted forvertical movement on the scaffold from top to bottom thereof whether ornot the scaffold is in vertically extended or collapsed position. Thecarriage 50 comprises a pair of substantially vertically extendinglaterally spaced angle irons 52 interconnected at their tops and bottomsby angle irons 54 to produce a rigid The space between the verticalangle irons 52 and the horizontal angle irons 54 is covered by a panel55. Pivoted adjacent the upper ends of the angle irons 52 is a platform56, the hinge connection being indicated at 58. In order to maintain theplatform 56 in proper position, suitable braces 60 are provided, whichas illustrated in Figure l rigidly support the platform 56 in horizontalposition.

In order to provide for substantial movement of the carriage 50 in anyposition of adjustment of the scaffold, rearwardly extending brackets 62and 64 are provided having openings therein forming journals for shafts66 on which are mounted wheels or rollers 68. A pair of rollers 68 aremounted adjacent the lower corners of the panel 55 and a second pair ofsuch rollers are mounted adjacent the sides of the panel intermediatethe upper and lower edges thereof, as best illustrated in Figure 3.

Carried by the vertical posts 14 at the front of the main frame 10 are apair of vertically extending roller receiving tracks 70. Carriedadjacent the front posts 32 of the movable frame 24 is a second pair ofroller receiving tracks 72. Each of the tracks, as well illustrated inFigure 8, includes a straight inwardly extending flange 74, an outerwall 75, and an arcuately curved forward wall 76, these being adapted topartly surround the corresponding roller 68 as illustrated in Figure 5,so as to prevent removal of the roller from its track except through anopen end thereof.

The stationary tracks 70 are connected to the posts 14 by a plurality ofbrackets 80 as illustrated in Figure 7, which are bolted or otherwisesecured to the inwardly extending flange of the posts14 by bolts 82',and are bolted to the wall 75 of the tracks 70 by bolts 84. It will beobserved that the-heads of the bolts 84 are countersunk to avoidinterference with movement of the rollers in the tracks. Adjacent theupper end of the main frame 10, as best illustrated in Figure 9, thereare provided brackets -36 which interconnect the posts 14 and the tracks70. The bracket 86 provides a web 88 secured to the track 70 by means ofrivets 90, these rivets also serving to secure a pair of bracket members92 in position, the bracket members 92 being separated at their upperends as illustrated in Figures 1 and 2 to provide openings formingjournals for sheaves 94. The track members 72 are secured to andvertically movable with the movable frame 24.

As best illustrated in Figure 8, the movable frame 24 is provided withthe angle iron 36 extending transversely across and interconnecting theforward portions of the longitudinally extending angle irons 34. Thevertically movable tracks 72 are connected adjacent their bottoms to theangle irons 36 by suitable means such as the rivets indicated at 96.

As best seen in Figure 9, the cross piece 44 is riveted or otherwisesecured as indicated at 100, to the mid-portion of the trackway 72, theends of the angle iron or cross piece 44 being connected to thelongitudinally extending flanges 98 of the front corner posts 32 by thebrackets 45. As best seen in Figure 1, the cross piece or angle iron 42may also be similarly connected to the upper ends of the tracks 72.

It will be recalled that the front posts 14 of the main frame are notdirectly interconnected at their upper portions and this of course isfor the purpose of permitting passage therethrough of the means whichserve to interconnect the movable frame 24 and the carriage 50. However,a construction is provided which supports the upper ends of the posts 14against lateral displacement and this construction is best illustratedin Figure 9. As seen in this figure, the stationary front corner posts14 of the main frame comprise the rearwardly or longitudinally extendingflanges 103, and inwardly or transversely extending flanges 104. Thebracket 86 which connects the angle iron 14 to the stationary tracksections 70 carries a spacer block 106 to which is secured a plate 108,suitable securing means such as the bolt 110 being provided. it will beobserved that the stationary corner post 14, the bracket 86, the spacerblock 106, andthe plate 108 together provide surfaces which confrontportions of the vertically movable corner post 32 in four directions.The corner post 32 comprises the rearwardly or longitudinally extendingflange 98 and an inwardly or laterally extending flange 114. Morespecifically, the inner surface of the rearwardly extending flange 103confronts or engages the outer surface of the rearwardly orlongitudinally extending flange 98 of the corner post 32. The rearwardlyfacing surface of the flange 104 of the corner post 14 engages orconfronts the forwardly facing surface of the inwardly extending flange114 of the corner post 32. The spacer block 106 engages or confronts theend surface of the flange 114. The forwardly facing surface of the plate108 engages or confronts the rearwardly directed surface of the flange114. The outer edge of the plate 108 engages or confronts the innersurface of the rearwardly extending flange 98 of the post 32.

It will be recalled that the corner posts 32 are rigidly interconnectedat their tops, bottoms and mid-portions by cross members. From theforegoing it will be apparent that the rigid interconnection between thecorner posts 32 of the movable frame 24 thus provides an adequatesupport for the upper portions of the corner posts 14 of the main frame10.

As well illustrated in Figures 8 and 9, the track sec tions and 72 aredirectly adjacent to each other and are so spaced that each receives oneof the rollers 68 carried by each of the brackets 62. Thus, when themovable frame 24 is in its lower or collapsed position, each of therollers 68 is engageable in a pair of adjacent tracks 70 or 72. However,when the movable frame 24 is elevated to its uppermost position it ispossible to elevate the carriage 50 to the position illustrated inFigure 1 and still maintain adequate support therefor. At this time thesets of rollers 68 most closely adjacent to the carriage 50 move out ofthe open upper ends of the tracks 70 but the outermost of the pairs ofrollers remains in the tracks 72. Thus, at all times at least fourrollers are engaged in trackways so as to provide adequate support forthe carriage.

As best seen in Figure 11, means may be provided for mounting a hopperon the vertically movable carriage 50. In this case the upper ends ofthe upper track 72 include an arcuate portion 122 and as the carriage 50reaches the upper end of the track 72 it enters upon the arcuatelycurved portion 122, thus tipping the hopper to the position illustratedin Figure 11. It will of course be appreciated that the curved portions122 of the track 72 may be caused to tip either forwardly or rearwardly.In the case where the covered portions of the track tip forwardly, thehopper may be caused to dump into a receptacle located in front of thescaffold. In Figure 11 however, the tracks are illustrated as curvedrearwardly and there is shown a receptacle 124 which will be carried atthe top of the movable frame 24, into which the contents of the hopper120 may be dumped.

Referring now to Figure 12 there is illustrated another variation of thepresent invention, in which case the carriage 50 is provided with alower platform 126 held in position by supporting arms 123. Spacedupwardly from the platform 126 is a railing 130 which will provide asafety feature for a man standing upon the platform 126. If desired, asection of the railing 130 may be movably associated with the remainderof the railing to permit ready access to the platform, after which themovable section of the railing may be replaced. Conveniently, themovable section of the railing may be hinged at one end to the carriageand have a releasable locking engagement at its free end with theremaining portion of the railing.

Power means are provided for selectively raising and lowering themovable frame 24 relative to the main frame 10, and for selectivelyraising and lowering the carriage 50.

As best illustrated in Figures l4, the means for raising and loweringthe movable frame 24 comprises a pair of cable Winding drums 132 carriedon a shaft 134, mounted in suitable bearings indicated at 136 which arecarried by the longitudinally extending main frame members 16. Sheaves138 are provided adjacent the lower rear corners of the main frame andsheaves 140 are provided adjacent the upper rear corners of the mainframev In like manner, sheaves 142 are mounted adjacent the lower frontcorners of the main frame, and sheaves 94 previously referred to arecarried by the main frame adjacent the top front corners thereof. A pairof cables 144 are provided each associated with one of the drums 132 andthe sheaves 138, 140, 142 and 94. One end of each of the cables 144 issecured to the lower portion of the movable frame 24 as indicated'at 146in Figure 1, and the opposite end of each of the cables is secured to acorresponding point at the forward ends of the movable frame 24 asindicated at 148 (Figure 2 and 3).

Reference is now made to Figure 13 to illustrate a useful modificationof the cable winding drums 132. Each of the drums as illustrated inFigure 13 is provided with a radially extending flange 150 at one endthereof and these flanges 150 are in turn provided with diametricallyopposite outwardly opening cable receiving notches 152. The cable 144 isinitially connected over the sheaves and secured at its ends to thelower corners of the movable frame 24 as previously described, in such away as to leave a certain amount of slack or looseness in the cable.This permits producing a bight in an intermediate portion of the cableadjacent one of the drums 132 and the cable is introduced through thenotches 152 as illustrated in Figure 13 so that the bight of the cable,indicated at 154, is located outwardly of the drum by the flange 150,and the leads of the cable 144 extending away from the drum are locatedto overlie the drum. With the parts in the relationship illustrated inFigure 13, 180 rotation of the drum and flange brings the leads of thecable 144 into engagement with the periphery of the the drum and furtherrotation winds up both leads of the cable simultaneously. The foregoingconstruction is highly desirable in that it permits ready separation ofthe cable from the main frame without disengaging its ends from theirsecurement to the movable frame.

The shaft 134, as best illustrated in Figure 4, is provided with acombined pulley and brake member 160 and is connected by a pulley belt162 to a driving pulley 164 mounted on a drive shaft 166. Suitablyassociated with the brake drum 168 is a brake diagrammatically indicatedat 170 which is adapted to lock the brake and hence the shaft 134against rotation. An electric motor 172 is mounted on the main frame andincludes a worm 174 meshing with a worm wheel 176 keyed or otherwisesecured to the shaft 166. The pulley 164 is axially movable on the shaft166 between a first position in which it is splined to the shaft andhence rotatable therewith, to a second position in which it is freelyrotatable on the shaft. Suitable means for effecting driving engagementbetween the pulley 164 and the shaft 166 are well known and are notillustrated or described in detail at this point. From the foregoing itwill be observed that when the driving pulley 164 is in position to bedriven by the shaft 166, rotation is imparted to the shaft 134 and hencethe cable winding drums 132 will be driven in one direction or the otherdepending upon the direction of rotation of the motor 172, thus raisingor lowering the movable frame 24.

Rigidly secured at all times to the shaft 166 is a second cable windingdrum 177 to which is secured a cable 178 movable around a sheave 180carried by the cross bar 18 at the lower end of the main frame 10, andthence upwardly over a sheave 182, the end of the cable 178 beingconnected to an intermediate point of the cross bar 54 of the carriage50. Thus, when the motor is actuated the carriage 50 may be raised orlowered in accordance with the direction of actuation of the motor.

With the foregoing detailed description in mind, it will be observedthat by suitable actuation of the motor the movable frame 24 may beraised and lowered and may be locked in any desired elevated position byengagement of the brake 170. Moreover, the carriage 50 may beselectively raised or lowered from a lowermost position to an elevatedposition determined by the amount of elevation of the movable frame 24.

It will be observed in Figure 1 that the platform 56 of the carriage 50is located substantially above the top of the movable frame 24. This isa very desirable feature since it permits locking of the movable frame24 in a position such that it will clear overhead structure in abuilding for ready movement thereon, and at the same time permitselevation of material on the platform 56 to a point substantially abovethe top of the movable frame 24.

The drawings and the foregoing specification constitute a description ofthe improved extensible scaffold in such full, clear, concise and exactterms as to enable any person skilled in the art to practicethe'invention, the scope of which is indicated by the appended claims.

What we claim as our invention is:

1. An extensible scaffold comprising a lower frame having a first pairof vertically extending tracks carried by said lower frame at the frontthereof, a movable frame guided for vertical movement on second pair ofvertically extending tracks carried by said movable frame at the frontthereof, each track of said second pair being parallel to, laterallyspaced from and in proximity to one of said first pair of tracks, avertically movable carriage at the front of said scaffold and having ateach side thereof a vertically spaced pair of guide devices, each ofwhich comprises a pair of elements, corresponding elements of each ofsaid pair of elements being vertically movable in and guided by one ofsaid first pair of tracks and the other element of each pair of elementsbeing vertically movable in and guided by one of said second pair oftracks.

2. An extensible scaffold as defined in claim 1 in which said movableframe is telescoped within said lower frame.

3. An extensible scaffold as defined in claim 1 in which said trackscomprise channel members and said elements comprise rollers.

4. An extensible scaffold as defined in claim 3 in which said channelmembers are shaped to surround said rollers to an extent sufficient toprevent movement of said rollers laterally out of said channels.

5. An extensible scaffold as defined in claim 1 comprising a motor onsaid lower frame, and lift means operated by said motor for selectivelyraising said movable frame and said carriage.

6. An extensible scaffold as defined in claim 5, said lift meanscomprising drum and cable means for raising and lowering said carriage,a connection between said motor and drum means, a second drum and cablemeans for raising and lowering said movable frame, and means forselectively connecting and disconnecting said motor and second drummeans.

7. An extensible scaffold as defined in claim 4 in which each of saidpairs of tracks are disposed with the open side of the channel membersin confronting relation, and the tracks of the pair carried by saidmovable frame are positioned directly in rear of the tracks of the paircarried by said lower frame.

8. An extensible scaffold as defined in claim 1 in which said carriageincludes a paltform and a platform support extending downwardlytherefrom, the uppermost of said pair of guide devices at each side ofsaid carriage being disposed substantially below said platform toprovide for elevation of said platform above the top of said movableframe.

9. An extensible scaffold comprising a redtangular lower frame elongatedfrom front to rear and having a pair of front and a pair of rear cornerposts, means interconnecting the tops and bottoms of said rear posts,means interconnecting the top and bottom of each rear post with the topand bottom of the corresponding front corner post, means interconnectingthe bottoms of said front posts, the space between said front cornerposts upwardly from the bottoms thereof being unobstructed, a movableframe guided for vertical movement within said lower frame and havingfront and rear corner posts guided for vertical movement by thecorresponding corner posts of said lower frame, means interconnectingthe tops and bottoms of each corner post of said movable frame to thetops and bottoms of the adjacent corner posts thereof, means carried bythe front corner posts of one of said frames slidably engaging the frontcorner posts of said other frame to prevent separation between the upperportions of the front posts of said lower frame, a first pair ofvertically extending tracks on said lower frame, each of which isadjacent to and carried by a front corner post thereof, a second pair ofvertically extending tracks on said movable frame, each of which isadjacent to and carried by a front corner post thereof parallel to butspaced laterally from the track carried by the adjacent front cornerpost of said lower frame, a vertically movable carriage having at eachside thereof a pair of vertically spaced guide devices, each guidedevice comprising a pair of elements, one of which is received by atrack said lower frame, a

carried by said lower frame and the other of which is received in atrack carried by said movable frame.

10. A scaffold as defined in claim 9 in Which each pair of trackscomprises channel members disposed with the open sides thereof inconfronting relation, and in which said elements comprise rollersreceived in the channels of saidv channel members.

11. A scatfold as defined in claim 10 in which the tracks of saidfirstpair of tracks are positioned in front of the tracks of said secondpair. of. tracks.

12. A scaffold as defined in claim 10, the upper ends of said first pairof tracks being open to provide for movement. of the rollers out of. theupper end thereof upon upward movement of said carriage while saidmovable frame is in elevated position.

References Cited in file of this patent UNITED STATES PATENTS Dye Mar.11, 1884 Miller Nov. 23, 1920 Green Apr. 24, 1928 Artini Apr. 23, 1940Eypper Oct. 28, 1947 Moon Aug. 28, 1951 Boedecker et al. Oct. 2', 1951Campbell Mar. 11, 1952 Segal July 14, 1953 Badik et al. Aug. 18, 1953

